We propose to carry out a study of the segragation behavior fo the PiZ and PiS alleles of the alpha-1 antitrypsin (alpha 1AT) system for the purpose of verifying three recent reports of significant segregation distortion. We further propose to study the recombination behavior of alpha 1AT with Gm since there appears to be suppression of crossing over between these loci in persons heterozygous for the PiZ allele. Additionally, we propose to investigate an unrelated linkage group to determine if the reported PiZ allele specific suppression of recombination is generalized phenomenon which affects the total genome. Finally, we propose to investigate the reproductive performance of various alpha 1AT mating types to determine if the selective advantage for the PiZ allele, resulting from the alleged segregation distortion, is balanced by decreased fertility in deficient homozygotes. The methods to be used include standard segregation analysis of backcross and intercross mating with the latter corrected for ascertainment bias. The linkage analysis will employ the maximum likelihood computer program LIPED. Alpha-1 antitrypsin phenotypes will be determined by the immunoelectrophoretic "rocket" technique, electrophoresis in agarose gel and acid starch-gel electrophoresis with crossed immunoelectrophoresis, and by isoelectric focusing in polyacrylamide gel. Standard procedures will be used to type Gm, Rh and PGM1.